Electrochemical DNA sensor for Neisseria meningitidis detection

Meningitis sensor based on nucleic acid probe of Neisseria meningitidis has been fabricated by immobilization of 5'-thiol end labeled single stranded deoxyribonucleic acid probe (ssDNA-SH) onto gold (Au) coated glass electrode. This ssDNA-SH/Au electrode hybridized with the genomic DNA (G-dsDNA/Au) and amplified DNA (PCR-dsDNA/Au) has been characterized using atomic force microscopy (AFM), Fourier transforms infrared spectroscopy (FT-IR) and electrochemical techniques. The ssDNA-SH/Au electrode can specifically detect upto 10-60 ng/microl of G-dsDNA-SH/Au and PCR-dsDNA-SH/Au of meningitis within 60s of hybridization time at 25 degrees C by cyclic voltammetry (CV) using methylene blue (MB) as electro-active DNA hybridization indicator. The values of sensitivities of the G-dsDNA-SH/Au and PCR-dsDNA-SH/Au electrodes have been determined as 0.0115 microA/ng cm(-2) and 0.0056 microA/ng cm(-2), respectively with regression coefficient (R) as 0.999. This DNA bioelectrode is stable for about 4 months when stored at 4 degrees C.